1. Field of the Invention
The invention pertains to the field of hydraulic tensioners. More particularly, the invention pertains to a hydraulic tensioner with a band type check valve.
2. Description of Related Art
In automobiles, hydraulic tensioners may be applied to a timing system or an auxiliary drive (e.g. oil pump) system. A hydraulic tensioner generally includes a housing, a piston slideably engaging the housing biased in a protruding direction by a spring, and a fluid chamber defined by the piston and the housing. During operation of the tensioner, external force from a chain or belt is imparted on the distal end of the piston. The force on the distal end is balanced by the tensioner spring load and hydraulic pressure in the chamber. Over time, the volume of the chamber may increase as the piston slides away from the housing, creating a need for more hydraulic fluid to fill the chamber. Hydraulic fluid may also need to be replenished in the chamber as fluid leaks out of the chamber.
There is a need in the art for a hydraulic tensioner with a low-cost check valve to facilitate replenishing the hydraulic fluid within the chamber, which is also simple to manufacture and reliable.